<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>浮动</title>
        <style>
            *{
                margin: 0;
                padding: 0;
            }
            ul{
                width: 900px;
                height: 300px;
                background: cadetblue;
                position: fixed;
                right: 100px;
                top: 40px;
            }
            li:nth-child(3){
                width: 300px;
                height: 200px;
            }
            li{
                width: 150px;
                height: 150px;
                background: pink;
                float: left;
                border: 1px solid red;
                list-style: none;
            }
        </style>
    </head>
    <body>
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </body>
</html>